No. If a police officer witnesses a crime, she can make an arrest. If police arrive on the scene of a crime (normally a felony) and there are witnesses to the crime, they may develop enough probable cause to arrest you right there. If the police investigate a past felony, they will need to secure a warrant (capias).
In misdemeanor cases in Florida that officers to not witness the offense committed, police do not get warrants unless after a summons has been issued, served and the subject of the summons does not appear in court. Generally, police are required to have a warrant to arrest you in your home, unless an emergency situation exists.
Additionally, there are exceptions to law enforcement officials needing a proper warrant before performing a search and seizure:
- the search was conducted incident to a lawful arrest
- search of an automobile
- search conducted in plain view
- search conducted with the defendant's consent to search their person or their property
- search conducted during an investigatory stop and frisk
- searches taking place after hot pursuit of a suspect.